This is a proposal to assess the effectiveness of sustained release anticancer or antineoplastic drug capsules, which have been developed in our laboratories. These are implantable systems for the continuous release of established anticancer compounds to target sites. In the past few years, in the course of the development of medicated contraceptive devices, we have made available, and carefully studied, a considerable number of polymeric sustained release capsules or systems. Various classes of drugs, as well as polymers, have been encountered, and it was evident to us that these facilities, polymeric systems and experience utilized in the development of sustained release medicated contraceptive devices, can be conveniently extended to the development of sustained, release antineoplastic drug systems or capsules. Consequently, a number of such antineoplastic drug capsules or systems are now available for in vivo testing and evaluation. The proposed study of these anticancer, drug-releasing systems includes the determination of polymer stability, drug diffusion rate, drug capsules' useful lifetime, and the toxicity of locally implanted antineoplastic drug capsules in experimental animals. The possibility of enhancing the effective use of certain antineoplastic compounds, by the development of such capsules, or systems, for continuous, controlled and local administration, seems probable. However, until these capsules or systems undergo reasonably comprehensive in vivo testing in experimental animals, this possibility remains to be investigated. We propose to test the effectiveness and advantages of the sustained-release, implantable, anti-neoplastic drug capsules developed. Details for testing procedures are explained in the main text.